Aging is a natural process not yet totally understood. It appears to be genetically controlled and can be accelerated by environmental, dietary, and pathological factors. At the cellular or molecular level, aging is considered as the result of the inability of an organism to respond adaptively to environmental changes. As people age, the process of self-renewal or replacement of skin cells slows down.
The skin has three layers: the epidermis, the dermis, and the hypodermis. The epidermis, the outmost layer, is filled with strata of specialized skin cells known as keratinocytes. These cells start out in the deepest layer of the epidermis and migrate to the skin surface. During this process, they lose moisture and are eventually sloughed off. In young people, this process takes about 4 weeks to travel to the surface. In people of age over 50, it can take about 5.5 weeks. The dermis, the layer beneath the epidermis, contains blood vessels that nourish the skin cells and the structural elements e.g., collagen and elastin, which keep the skin firm and springy. Aging results in fewer keratinocyte layers and, thus, less skin stem cell self-renewal and replacement. Also, the aged skin lost collagen and elastin poorly, leading to thin and papery-look appearance. Consequently, wrinkles form. This slow, concurrent losses of dermal cellular and structural elements, thickness, and elasticity, together with wrinkle and segment formation, are the most obvious indicators of skin aging.
Various compositions and methods have been used for regulating undesirable skin surface texture, such as fine lines, wrinkles, pores, and the like. However, many of them are ineffective or cause allergy and other side effects. Thus, there is a need for a more effective and safer cosmetic composition.